scholarly journals Automated platform for consistent part realization with regenerative hybrid additive manufacturing workflow

2021 ◽  
Author(s):  
Oliver Avram ◽  
Chris Fellows ◽  
Marco Menerini ◽  
Anna Valente
Keyword(s):  
Additive Manufacturing ◽  
Deposition Process ◽  
Hybrid Process ◽  
Full Potential ◽  
Manufacturing Strategy ◽  
Process Chains ◽  
Part Inspection ◽  
Automated Platform

AbstractNowadays, the role of hybridization within the wider manufacturing ecosystem gains significant momentum with multiple commercial solutions already available on the market. Despite the very promising benefits of combining and selectively exploiting the advantages of additive and subtractive technologies on the same machine, hybrid additive manufacturing is far from reaching its full potential. One of the central limitations of existing hybrid process chains is the lack of a harmonized, structured and automated workflows to support an adaptive manufacturing strategy. This work is motivated by the need to bridge this gap and to capture the logic behind an adaptive hybrid process chain with the aim to support the achievement of enhanced product quality and improved operational efficiency in hybrid additive manufacturing. The paper discusses the implementation of a hybrid CAx platform and the underlying methodology aiming at the dynamic reduction of variabilities associated with the laser metal deposition process. The hybrid workflow identifies the most adapted sequence and planning of additive and subtractive operations while considering part inspection as an in-envelope functionality to quantify the geometrical and dimensional part deviations and to trigger the regenerative mechanism. The methodology is demonstrated on a hybrid machine by deploying laser ablation for the in situ removal of build deviations and an adapted deposition operation as part of a regenerative strategy leading to higher part confidence.

scholarly journals Hybrid subtractive–additive manufacturing processes for high value-added metal components

2020 ◽  
Vol 111 (3-4) ◽  
pp. 645-655
Author(s):  
Panagiotis Stavropoulos ◽  
Harry Bikas ◽  
Oliver Avram ◽  
Anna Valente ◽  
George Chryssolouris
Keyword(s):  
Additive Manufacturing ◽  
Value Added ◽  
Hybrid Process ◽  
Process Window ◽  
Manufacturing Processes ◽  
Advanced Manufacturing ◽  
Optimal Process ◽  
Structured Decision Making ◽  
Process Chains ◽  
Part Inspection

Abstract Hybrid process chains lack structured decision-making tools to support advanced manufacturing strategies, consisting of a simulation-enhanced sequencing and planning of additive and subtractive processes. The paper sets out a method aiming at identifying an optimal process window for additive manufacturing, while considering its integration with conventional technologies, starting from part inspection as a built-in functionality, quantifying geometrical and dimensional part deviations, and triggering an effective hybrid process recipe. The method is demonstrated on a hybrid manufacturing scenario, by dynamically sequencing laser deposition (DLM) and subtraction (milling), triggered by intermediate inspection steps to ensure consistent growth of a part.

Threshold Value of Particle Concentration in EPD: Experimental Evidence with TiO2 Organic Suspensions

2009 ◽  
Vol 412 ◽  
pp. 51-56 ◽  
Author(s):  
Simona Radice ◽  
Stefano Mischler ◽  
Johann Michler
Keyword(s):  
Particle Concentration ◽  
Deposition Time ◽  
Threshold Value ◽  
Deposition Process ◽  
Suspension Systems ◽  
Limit Value ◽  
Coating Formation ◽  
Concentration Threshold

This study was triggered by our experience on electrophoretic deposition (EPD) with different suspension systems showing evidence of a particle concentration threshold, below which no deposit was formed. In this study, the role of particle concentration in the mechanism of EPD was investigated with a model system, consisting of isopropanol suspensions with TiO2 nanosized particles (d50 = 130 nm). The investigated concentration range was 0.01 - 0.4 vol% TiO2. Constant voltage EPD tests with variable particle concentration were performed for 1 min under different applied voltages (25 - 300 V corresponding to 62.5 - 750 V/cm). A longer deposition time (30 min) was tested for a lower concentration value (0.003 vol% TiO2). The deposition process was evaluated in situ by means of the current measured during EPD. The deposits obtained were characterized by weight and profile measurements and scanning electron microscope (SEM). The results confirmed the finding of a lower limit value of particle concentration, determining a threshold in the formation of an EPD coating. Above this threshold, proportionality between deposited mass and particle concentration was observed, in agreement with the equation of Hamaker. Below this threshold, the proportionality was lost with evidence of a lack of coating formation. A possible interpretation for this experimental finding was provided.

Nachbearbeitung additiv gefertigter Fräswerkzeuge/Exploiting the full potential by developing seamless process chains

2021 ◽  
Vol 111 (11-12) ◽  
pp. 818-823
Author(s):  
Tobias Kelliger ◽  
Christoph Zachert ◽  
Daniel Schraknepper ◽  
Thomas Bergs
Keyword(s):  
Additive Manufacturing ◽  
Cutting Tools ◽  
Design Guidelines ◽  
Full Potential ◽  
Process Chain ◽  
Post Processing ◽  
Additive Fertigung ◽  
Process Chains ◽  
Individual Design ◽  
Design And Production

Durch additive Fertigung können Zerspanwerkzeuge beanspruchungsgerecht und individuell designt und gefertigt werden. Um das volle ökonomische und ökologische Potenzial dieser Werkzeuge auszuschöpfen, ist eine übergreifende Prozesskettenbetrachtung von der Konstruktion über die Fertigung bis zur spanenden Nachbearbeitung nötig. Dabei müssen übergreifende Lösungen und Gestaltungsrichtlinien entwickelt werden.   Additive manufacturing enables an individual design and production of cutting tools that fulfills the requirements. However, the full economic and ecological potential can only be exploited by considering the entire process chain from design and production to post-processing. General solutions and design guidelines have to be developed.

scholarly journals A Hybrid Process Integrating Reverse Engineering, Pre-Repair Processing, Additive Manufacturing, and Material Testing for Component Remanufacturing

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1961 ◽  
Author(s):  
Xinchang Zhang ◽  
Wenyuan Cui ◽  
Wei Li ◽  
Frank Liou
Keyword(s):  
Heat Treatment ◽  
Additive Manufacturing ◽  
Reverse Engineering ◽  
Impact Damage ◽  
Three Dimensional ◽  
Deposition Process ◽  
Material Testing ◽  
Hybrid Process ◽  
Metallic Component ◽  
Three Dimensional Models

Metallic components can gain defects such as dents, cracks, wear, heat checks, deformation, etc., that need to be repaired before reinserting into service for extending the lifespan of these parts. In this study, a hybrid process was developed to integrate reverse engineering, pre-repair processing, additive manufacturing, and material testing for the purpose of part remanufacturing. Worn components with varied defects were scanned using a 3D scanner to recreate the three-dimensional models. Pre-repair processing methods which include pre-repair machining and heat-treatment were introduced. Strategies for pre-repair machining of defects including surface impact damage, surface superficial damage and cracking were presented. Pre-repair heat-treatment procedure for H13 tool steel which was widely used in die/mold application was introduced. Repair volume reconstruction methodology was developed to regain the missing geometry on worn parts. The repair volume provides a geometry that should be restored in the additive manufacturing process. A damaged component was repaired using the directed energy deposition process to rebuild the worn geometry. The repaired part was inspected in microstructure and mechanical aspects to evaluate the repair. The hybrid process solved key issues associated with repair, providing a solution for automated metallic component remanufacturing.

In-Situ Rheed Observation of Mocvd-Gan Film Growth

2001 ◽  
Vol 693 ◽  
Author(s):  
Masatomo Sumiya ◽  
Noritaka Ogusu ◽  
Kouhei Osada ◽  
Shunro Fuke
Keyword(s):  
Buffer Layer ◽  
Film Growth ◽  
Deposition Process ◽  
Film Deposition ◽  
Total Flow ◽  
Total Flow Rate ◽  
Gan Film ◽  
Lattice Mismatched Substrate

AbstractWe developed the MOCVD apparatus equipped with RHEED system, which enable us to observe in-situ and real time RHEED for GaN film growth in ~100mTorr of pressure. We attempted to grow GaN film with this MOCVD chamber in 100mTorr. The in-situ RHEED was subsequently observed along the film deposition process in order to understand both the role of buffer layer and the mechanism of GaN film growth by MOCVD on highly lattice-mismatched substrate like sapphire. The results indicate that oxygen removed from the sapphire surface was observed during its cleaning in H2 flow at 1100°C. The dependence of re-crystallization and evaporation of the buffer layer on the annealing ambient was also detected. Although the nitrogen was slightly deficient, HT-GaN film with smooth surface was obtained in 100mTorr by adding H2 gas and reducing total flow rate. In preliminary deposition, the RHEED oscillation-like was observed in MOCVD-GaN growth. Thus, our developing deposition system has a potential to understand the growth mechanism with atomic level.

Hidden parameters in the plasma deposition of microcrystalline silicon solar cells

2007 ◽  
Vol 22 (7) ◽  
pp. 1767-1774 ◽  
Author(s):  
M.N. van den Donker ◽  
B. Rech ◽  
R. Schmitz ◽  
J. Klomfass ◽  
G. Dingemans ◽  
...  
Keyword(s):  
Solar Cells ◽  
Process Parameters ◽  
Gas Flow ◽  
Plasma Deposition ◽  
Deposition Process ◽  
Additional Parameter ◽  
Hydrogen Dilution ◽  
The Stability

The effect of process parameters on the plasma deposition of μc-Si:H solar cells is reviewed in this article. Several in situ diagnostics are presented, which can be used to study the process stability as an additional parameter in the deposition process. The diagnostics were used to investigate the stability of the substrate temperature during deposition at elevated power and the gas composition during deposition at decreased hydrogen dilution. Based on these investigations, an updated view on the role of the process parameters of plasma power, heater temperature, total gas flow rate, and hydrogen dilution is presented.

Phononic Crystal Artifacts for Real-Time In Situ Quality Monitoring in Additive Manufacturing

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Xiaochi Xu ◽  
Chaitanya Krishna Prasad Vallabh ◽  
Zachary James Cleland ◽  
Cetin Cetinkaya
Keyword(s):  
Wave Propagation ◽  
Additive Manufacturing ◽  
Real Time ◽  
Phononic Crystal ◽  
Production Method ◽  
Structure Design ◽  
Full Potential ◽  
Real Time Monitoring ◽  
Bond Quality

Additive manufacturing (AM) is rapidly becoming a local manufacturing modality in fabricating complex, custom-designed parts, providing an unprecedented form-free flexibility for custom products. However, significant variability in part geometric quality and mechanical strength due to the shortcomings of AM processes has often been reported. Presently, AM generally lacks in situ quality inspection capability, which seriously hampers the realization of its full potential in delivering qualified practical parts. Here, we present a monitoring approach and a periodic structure design for developing test artifacts for in situ real-time monitoring of the material and bonding properties of a part at fiber/bond-scale. While the production method used in current work is filament based, the proposed approach is generic as defects are always due to materials in a bonding zone and their local bonding attributes in any production modality. The artifact design detailed here is based on ultrasonic wave propagation in phononic coupons consisting of repeating substructures to monitor and eventually to assess the bond quality and placement uniformity—not only for geometry but also for defect states. Periodicity in a structure leads to the dispersion of waves, which is sensitive to geometric/materials properties and irregularities. In this proof-of-concept study, an experimental setup and basic artifact designs are described and off-line/real-time monitoring data are presented. As a model problem, the effects of printing speed on the formation of stop bands, wave propagation speeds and fiber placement accuracy in samples are detected and reported.

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